# Algorithm: Depth-First Search (DFS)
# Type: Graph Traversal, Recursive/Stack-based
# Time Complexity: O(V + E) where V = vertices, E = edges
# Space Complexity: O(V) for recursion stack or explicit stack

function DFS(graph, start):
    create visited set

    function dfs_visit(node):
        mark node as visited
        for each neighbor in graph[node]:
            if neighbor not visited:
                dfs_visit(neighbor)

    dfs_visit(start)